[ On Thursday, August 15, 2002 at 08:53:25 (+0200), Thomas Michael Wanka wrote: ]
> Subject: Re: old monochrome monitor repair hints?
>
> Actually my experience is not that great, but that sounds more 
> like a high frequenzy generator problem.

In this case it's definitely the switching power supply (which also has
high frequency oscillators of course).

Originally I thought it was the high-voltage module, and I didn't hope
for any repair.

However I forgot to mention that I sounded it out by putting a plastic
rod on various components.  I didn't need my ears nearby to feel the
thunk produced in various capacitors and the bigger transformer coil on
the PS module....  :-)

Unfortunately the vibration was not significantly higher in any one
component (and even if it were that would not likely be the bad one, but
rather just the focus of the failure mode), and visually all components
look fine (though they all do show signs of having been baked in the
oven that is the chassis).

I guess it might not hurt to just replace all of the electrolytic caps....
If one's dry the others may be nearly dry.

> I have at least one 21" philips monitor around that has the same
> problems (just that the philips firmware shuts almost everything down
> and reports an error - and I never knew why a monitor has a rs232
> port).

Yup, modern multisync monitors are all computer controlled.  Good
multisync monitors have fail-safe code in their firmware to prevent them
from blowing up when something catastrophic happens in the video
circutry or when they're asked to run at stupid frequencies.  I saw the
aftermath of an old multisync without such protection (or it failed)
(big brown spot on the top of the case where the owner said flames shot
out), and then of course there were the old original IBM PC monitors
that were not multisync but tried to be when they were disconnected from
their sync signals and let to run free....  :-)  There was lots of smoke
in those little monsters.

-- 
								Greg A. Woods

+1 416 218-0098;            <g.a.woods@ieee.org>;           <woods@robohack.ca>
Planix, Inc. <woods@planix.com>; VE3TCP; Secrets of the Weird <woods@weird.com>